1. Field of the Invention
The invention is related to the field of wireless networks, and in particular, to systems and methods of filtering spam destined for mobile communication devices communicating with a wireless network.
2. Statement of the Problem
Many people use computers daily at work or at home to access email accounts. One problem facing computer users is receiving spam in their email accounts. Spam is typically understood to be unsolicited emails or junk emails. From the sender's point-of-view, spam is a form of bulk email, often to a list obtained by companies that specialize in creating email distribution lists. To the receiver, spam is junk email that needs to be deleted and is a risk of including a virus. Spam is roughly equivalent to unsolicited telephone marketing calls except that the user unfortunately pays for part of the spam since everyone shares the cost of maintaining the Internet.
To protect against spam, some users install a spam filter on their computer or network server. A spam filter is a program that is used to detect unsolicited and unwanted emails and prevents those emails from getting to a user's inbox. Like other types of filtering programs, a spam filter looks for certain criteria on which it bases judgments. For example, the simplest and earliest versions can be set to watch for particular words in the subject line of messages and to exclude these from the user's inbox. This method is not especially effective as legitimate messages may be blocked while actual spam is let through. More sophisticated programs attempt to identify spam through suspicious word patterns or word frequency.
Cell phones and other mobile communication devices are now equipped to transmit and receive text messages, such as Short Message Service (SMS) messages. Some cell phones are also equipped to transmit and receive multi-media messages, such as digital pictures taken by a camera phone. Unfortunately, current spam filters used on computers have not been effectively implemented to protect cell phones and other mobile communication devices from receiving spam in the form of SMS and similar-type messages. The current spam filters for computers are tailored for HTTP messages, not text or multi-media messages used by current cell phones.
For a typical SMS text message, the sender enters a number of the destination phone and a text message. The sender's phone transmits signaling (e.g., SS7, C7, or other signaling) over a signaling path through a signaling gateway to an SMS Center (SMSC). If a bearer path is established to the SMSC, the sender's phone transmits the text message to the SMSC over the bearer path. The SMSC can later forward the text message to the destination phone. Unfortunately, if the SMS message comprises spam, there is currently no effective way to block the spam. If the SMS message comprises spam and the SMS message reaches the SMSC, the SMSC will currently transmit the SMS message to the destination phone without checking to see if the SMS message comprises spam.
The user of the destination phone may become dissatisfied with his/her service provider if the user receives too much spam. Thus, it is a problem that facilities do not exist that block spam SMS messages (and other text or multi-media messages that comprise spam) destined for a cell phone or similar mobile communication device.